Are your players going to make more than $350 each for the poker room?
If you take the profit from like 10 players and average, is it more than that?
If it is less the room will soon dump you and possibly tell the others that you accept deals you know you cannot live up to and no one will do deals with you again.
CPA can even out variance for you. If you bring enough top players to make up for the room’s expense, they will swallow a month of bad players and pay you in full anyway. But you have to deliver more than they pay overall in order for them to continue.
So in effect you sell your right to any whales and large players for a more consistent income.
If you do not produce the whales you are out and your reputation is damaged. If you do produce the whales you likely are losing money.
Occasionally this works out to a proper average and you just get more even payments.